A sensing fiber has two functions of “transmitting” and “sensing” at the same time. There are a variety of sensors based on a fiber sensing technology. The same parameter may be measured by different types of sensors, but the core idea of the fiber sensing technology is to detect the modulation of light by external parameters. The sensing fibers are divided into an intensity modulation type, a phase modulation type, a frequency modulation type, a wavelength modulation type, a polarization state modulation type, and other types according to the modulated theory of the light in the fiber. With the development of light information and sensing technology, the fiber sensing technology has been greatly improved, and has the advantages on sensing manner, sensing principle, signal detection and processing, and other aspects that the traditional electric sensor does not have.
The acoustic emission technology is an advanced non-destructive testing technology, which finds out the damage, fracture, deformation and other information in a tested object through detecting and analyzing an acoustic wave sent by the tested object itself. The technology is widely used in petroleum, aviation, construction and other fields. A key component of acoustic emission is an acoustic emission sensor for collecting and detecting the acoustic wave. The traditional acoustic emission sensor manufactured through piezoelectric ceramics or piezoelectric crystal materials has the defects of poor anti-electromagnetic interference capability and short signal transmission, and the defects of poor anti-electromagnetic interference capability and short signal transmission can be prevented through integrating the fiber sensing technology with the acoustic emission technology. Moreover, the fiber sensing technology can remedy the capability of the acoustic emission that the temperature and other information cannot be monitored. Therefore, integrating the fiber sensing technology with the acoustic emission sensing technology will greatly extend the sensing monitoring and detection capabilities of a structure, but how to collect and enhance the acoustic wave in the acoustic emission technology preferably and how to arrange the sensing fibers preferably have not been reported yet in the current field of integrating the fiber sensing technology with acoustic emission technology.